As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Current information handling systems and methods for controlling data transfer to and from a memory storage system and determining battery health are known in the art. For example, FIGS. 1 and 2 are prior art figures that illustrate the current methods of determining battery health. FIG. 1 shows a prior art information handling system 100 having a server 101 coupled to a memory storage system 102. The information handling system 100 may include a storage memory controller card within or independent of the server 101. FIG. 2 shows a prior art storage memory controller card with battery back up and a discharge circuit that may be coupled to a redundant array of independent disks (RAID) memory system. A RAID system is a data storage system wherein data is distributed across a group of storage hard disk drives functioning as a small storage unit. Often, information stored on each disk is duplicated on other disks in the array, creating redundancy to ensure no information is lost if disk failure occurs. An exemplary RAID controller circuit 200, for example a PowerEdge RAID Controller (PERC) cards available from Dell, Inc., is shown in FIG. 2. As shown in FIG. 2, the controller circuit 200 includes a cache memory 202 to improve storage performance as described below. The cache memory 202 may be for example DRAM memory such as 256 MB DDR2 memory. During operation of the controller circuit 200, user data may be transferred to/from the controller circuit 200 from/to the RAID hard disk drives (not shown in FIG. 2). As part of the transfer, prior art systems typically store data in the cache memory 202 as part of the transfer of the data to/from the RAID disk drives. If a system power loss occurs it is advantageous to be able to maintain the data transfer of the data that has already been staged in the memory cache. Thus, a backup battery 204 is utilized to provide power to the cache memory 202 so that the memory cache does not lose the data that has not yet been transferred. The battery power may thus power the memory cache until the system power becomes stable again so that data in the cache may then be reliably transferred to the RAID hard disk drives. In one example, the backup battery 204 provides power to the memory 202 via a DC to DC converter 203, which may provide a 1.8V 1 W power source to the memory 202.
Over time, the battery health can degrade such that the total charge capacity can be significantly less than that of the original battery rating. Such degradation will impact the ability to help ensure the proper transfer of data during a power loss as described above and it is desirable to determine if the battery has degraded to the point that it does not have sufficient power to accomplish this task. To determine the health of the battery 204, the controller circuit 200 performs a learn cycle, which includes discharging the battery 204 completely, then recharging it to its maximum capacity. During the recharge cycle, a management controller measures a charge rate and time to determine the total charge capacity of the battery 204, and thus its health. Current art methods of discharging a battery 204 utilize a set of power resistors to drain the charge from the battery 204 at a rate of 4 W. However, dissipation of this energy creates an undesirable temperature increase in a system that contains the controller card 200. Also requiring dissipation of the power over power resistors increases cost. Further, the use of multiple power resistors requires a significant amount of circuit board real estate. Also, the power dissipation of the battery 204 is completely lost to heat, which is environmentally inefficient. It will be recognized that in storage memory card controller applications a discharge of the battery is generally a rare occurrence and thus a separate technique is desired to determine if the battery is actually still capable of providing the desired power.
Other exemplary portions of the prior art controller card 200 will now be described. The battery 204 is charged by a charger 206 which is provided power through by a PCI Express X8 Card Edge Connector 205. The battery 204 sends power to a discharge circuit 211 which include power resistors 215 and a switch 217. When testing for the health of the battery 204, the discharge circuit 211 receives input from a RAID processor 208 which turns on the switch 217 and thus discharges the battery 204 through the power resistors 215. The Card Edge Connector 205 provides power to a second DC to DC converter 207. The DC to DC converter 207 provides a plurality of voltage supplies for operating the various components of the circuit during normal non-power loss situations (for example power is shown as being provided to the RAID processor 208). For example, the DC to DC converter 207 may be rated to provide 1.8V 21 W power. Power may be provided from the DC to DC converter 207 to the cache memory 202 through an isolation circuit 210. The isolation circuit 210 is responsive to power good logic 209. When a power loss situation occurs, power good logic 209 sends a signal to the isolation circuit 210 so that the input power supply line to the cache memory will be isolated from other circuitry (this isolates the input power supply line to receive battery power without the battery power being drained to other circuitry on the controller card 200).
It will be recognized that the problems described above relating to the undesirable power discharge techniques of the controller card are not limiting to the particular embodiment of a controller card described above. Thus, controller cards having other circuit designs may also have such undesirable power discharge techniques. It is desirable to have a system for controlling data transfer to and from a memory storage system that includes a backup battery in which battery health is monitored through a discharge cycle which lessens at least some of the problems described above.
In the past, notebook computers have employed a battery calibration function that allows the notebook computer battery to be discharged through a system load during a learn cycle such as occurs during an extended system shutdown. The discharge current value is pre-determined for such a calibration cycle based on the system configuration, such as the size of LCD panel, memory and speed of processor, etc.